How to remove Filters from post admin page?

This is a very similar question to the one you posted here: How to HIDE everything in PUBLISH metabox except Move to Trash & PUBLISH button Please check my answer. You would simply need to add the IDs of the elements you wish to hide.

You can traverse the DOM to target the elements you need:

#posts-filter .tablenav select[name=m],
#posts-filter .tablenav select[name=cat],
#posts-filter .tablenav #post-query-submit{
    display:none;
}